Node Manager weblogic -II
a Node Manager Restarts an Administration Server
The diagram in the slide illustrates the flow of a Node Manager restarting an administration server.
1. The Node Manager determines from the administration server process exit code that it requires a restart. Note that no user is involved.
2. The Node Manager obtains the username and password for starting the administration server from theboot.properties file, and the server startup properties from theserver/security/startup.properties file. These server-specific files are located in the serverdirectory for the administration server.
3. The Node Manager starts the administration server.
4. The administration server reads its configuration data and starts up.
Node Manager Restarts a Managed Server
The diagram in the slide illustrates the flow of a Node Manager restarting a managed server.
1. The Node Manager determines from Managed Server 1’s last known state that it requires a restart. Note that no user is involved.
2. The Node Manager obtains the username and password for starting Managed Server 1 from theboot.properties file, and the server startup properties from the startup.properties file. These server-specific files are located in the server directory for Managed Server 1.
3. The Node Manager starts the managed server.Note: The Node Manager waits RestartDelaySeconds after a server instance fails before attempting to restart it.
4. Managed Server 1 attempts to contact the administration server to check for updates to its configuration data. If it contacts the administration server and obtains updated configuration data, it updates its local cache in theconfig directory.
5. If Managed Server 1 fails to contact the administration server, and if Managed Server Independence mode (MSI) is enabled, Managed Server 1 uses its locally cached configuration data.
Node Manager Shuts Down a Server Instance
The diagram in the slide illustrates the flow of a Node Manager shutting down a server.
1. Through the Administration Console, an authorized user issues a shutdown command for Managed Server 1.
2. The administration server issues the shutdown command directly to Managed Server 1. If it successfully contacts Managed Server 1, Managed Server 1 performs the graceful shutdown sequence.
3. If in the previous step, the administration server fails to contact Managed Server 1, it issues a shutdown command for Managed Server 1 to the Node Manager on Machine B.
4. The Node Manager issues a request to the operating system to stop Managed Server 1.
5. The operating system ends the Managed Server 1 process.
Versions of Node Managers
Oracle WebLogic Server provides two versions of Node Managers: Java-based and script-based, with similar functionality. However, each version has a different configuration and security considerations.
The Java-based Node Managers run within Java Virtual Machine (JVM) processes. It is recommended that you run Node Managers as Windows services on Windows platforms and as operating system services on UNIX platforms, allowing the Node Managers to restart automatically when the system is rebooted.
Oracle provides native Node Manager libraries for Windows, Solaris, HP-UX, Linux on Intel, Linux on Z-Series, and the AIX operating systems.
Note: Node Managers are not supported on Open VMS, OS/390, AS400, UnixWare, or Tru64 UNIX.
This version of the Node Manager determines its configuration from the nodemanager.properties file.
For UNIX systems, Oracle WebLogic Server provides a script-based version of the Node Manager. This script is based on UNIX shell scripts, but uses Secure Shell (SSH) for increased security. SSH uses user-ID based security.
The script-based version does not provide as much security as the Java-based version. However, the advantage of script-based Node Managers is that they can remotely manage servers over a network that has been configured to use SSH. No additional server installation is required. The scripts merely have to be copied to the remote machine. Although scripted, the Node Manager can be easy to configure in some cases, and its feature set does not contain some of the capabilities of a Java Node Manager. For those more familiar with configuring Java SSL than RSH or SSH, a Java-based Node Manager can be just as easy to configure.
Determining Which Node Manager Version to Use
•Automatic Server Migration is supported by both the scripted version of Node Managers and the Java version of Node Managers. In previous releases of WLS, only the scripted version supported automatic server migration.
•If you are installing Oracle WebLogic Server on a Windows system, you must use a Java version of Node Manager. The scripted version of a Node Manager is not supported on Windows.
•The script-based Node Manager requires a much simpler security configuration than the Java version. Remote Shell (RSH) and SSH are easier to configure than Secure Sockets Layer (SSL), which is the method of security used by a Java version of Node Manager. The script version of a Node Manager also requires a smaller footprint than the Java version.
•The Java version of a Node Manager can be used with inetd on supported UNIX systems. inetd allows a Node Manager to be automatically restarted upon receiving a request on the configured port. The Java Node Manager is a running process that can also recover on its own in case of a full-machine shutdown. In the case where the Java Node Manager is restarted (automatically or manually), it will scan the domain directories for the servers it had previously managed or started and will automatically attempt to restart them. The scripted Node Manager is a passive process and is unable to do this.
Node Manager Default Behaviors
The Node Manager is ready to run after Oracle WebLogic Server is installed if you run the Node Manager and the administration server on the same machine, and use the demonstration’s Secure Sockets Layer (SSL) configuration. By default, the following behaviors are configured:
•You can start a managed server using the Node Manager through the Administration Console.
•The Node Manager monitors the managed servers that it has started.
Automatic restart of managed servers is enabled. The Node Manager restarts the server instances that it killed or that were killed by another method.
Configuring a Java-Based Node Manager
Except where noted, the configuration files apply to both Java-based and script-based Node Manager. The following files are located in <WL_HOME>/common/nodemanager.
•nodemanager.properties: This is the configuration file that is used by the Java-based version of the Node Manager.
•nodemanager.domains: This file contains mappings between the names of the domains managed by the Node Manager and their corresponding directories.
•nm_data.properties: This file stores the encryption data that the Node Manager uses as a symmetric encryption key. The data is stored in an encrypted form.
These files are located in other directories:
•nm_password.properties: This file stores a username/password pair that is specific to the Node Manager server that manages this domain. This is known as the Node Manager secret. The username and password are appended to a salt value (obtained from SerializedSystemIni.dat of the domain) and Secure Hash Algorithm (SHA) hashed. This file is located in DOMAIN_HOME/config/nodemanager.
•boot.properties: The Node Manager uses this file to specify a boot identity when starting a server. This file is located in domain-name/servers/server_name/data/nodemanager.
The following file has been deprecated but you may still see it around:
•nodemanager.hosts: This file contained a list of all the trusted hosts that could issue commands to the Node Manager. It was located in <WL_HOME>/common/nodemanager.
Reconfiguring the Startup Service for a Windows Installation
The <WL_HOME>/server/bin directory (where <WL_HOME> is the top-level directory for the Oracle WebLogic Server installation) contains uninstallNodeMgrSvc.cmd, a script for uninstalling the Node Manager service, and installNodeMgrSvc.cmd, a script for installing the Node Manager as a service.
1. Delete the Node Manager service using uninstallNodeMgrSvc.cmd.
2. Edit installNodeMgrSvc.cmd to specify the listen address and the listen port of the Node Manager. Make the same edits to uninstallNodeMgrSvc.cmd as you make toinstallNodeMgrSvc.cmd, so that you can successfully uninstall the service in the future.
3. Run installNodeMgrSvc.cmd to reinstall the Node Manager as a service, listening on the updated address and port.
Node Manager as a UNIX Daemon
Oracle WebLogic Server does not provide a command script for uninstalling and reinstalling the Node Manager daemon process. Refer to your operating system documentation for instructions on uninstalling existing daemons and setting up new ones.
1. Remove the Node Manager daemon process that the Oracle WebLogic Server installation process sets up.
2. At the command line, or in a script, reinstall the Node Manager daemon. You may want to view the contents of the installNodeMgrSvc.cmd file before setting up the new daemon. This cmd file is not installed on UNIX-based systems. Although this command file is Windows-specific, it illustrates the following:
-The key environment and local variables that must be defined
-The validation steps that you might want to include in a script that installs the Node Manager as a daemon
-The logic for setting default values for the listen address and port
Node Manager as a UNIX Daemon
Oracle WebLogic Server does not provide a command script for uninstalling and reinstalling the Node Manager daemon process. Refer to your operating system documentation for instructions on uninstalling existing daemons and setting up new ones.
1. Remove the Node Manager daemon process that the Oracle WebLogic Server installation process sets up.
2. At the command line, or in a script, reinstall the Node Manager daemon. You may want to view the contents of the installNodeMgrSvc.cmd file before setting up the new daemon. This cmd file is not installed on UNIX-based systems. Although this command file is Windows-specific, it illustrates the following:
-The key environment and local variables that must be defined
-The validation steps that you might want to include in a script that installs the Node Manager as a daemon
-The logic for setting default values for the listen address and port
Reviewing nodemanager.properties
The Node Manager properties define a variety of configuration settings for a Java-based Node Manager process. You can specify the Node Manager properties on the command line or define them in thenodemanager.properties file, which is created in the <WL_HOME>/common/nodemanagerdirectory the first time that Node Manager starts up after the installation of Oracle WebLogic Server. Values supplied on the command line override the values in nodemanager.properties.
nodemanager.properties is created in the directory specified in NodeManagerHome, whereNodeManagerHome is <WL_HOME>/common/nodemanager. If NodeManagerHome is not defined, nodemanager.properties is created in the current directory.
Each time you start a Node Manager, it looks for nodemanager.properties in the current directory, and creates the file if it does not exist in that directory. However, you cannot access the file until the Node Manager has started up once.
In many environments, the SSL-related properties in nodemanager.properties may be the only Node Manager properties that you must explicitly define. However, nodemanager.propertiesalso contains non-SSL properties that you might need to specify, depending on your environment and preferences. For example:
•For a non-Windows installation, it might be appropriate to specify the StartScriptEnabledand NativeVersionEnabled properties.
•If a Node Manager runs on a multihomed system, and you want to control the address and port that it uses, define ListenAddress and ListenPort.
Configuring a Script-Based Node Manager
The SSH Node Manager is a shell script, wlscontrol.sh, located in <WL_HOME>/common/bin/. The wlscontrol.sh file must exist on each machine that hosts the server instances that you want to control with the Node Manager. This script can be customized to meet site-specific requirements.
You must have an SSH client executable on each machine where the Node Manager or a Node Manager client runs. This script must also be in the path of the user ID that is running it. Typically, an SSH client is a standard part of a UNIX or Linux installation.
Configuring the nodemanager.domains File
The nodemanager.domains file specifies the domains that a Node Manager instance controls. Thus, stand-alone clients do not need to specify the domain directory explicitly.
This file must contain an entry specifying the domain directory for each domain the Node Manager instance controls, in this form:
<domain-name>=<domain-directory>
Example:
MedRecDomain=/u01/app/oracle/user_projects/domains/MedRecDomain
When a user issues a command for a domain, the Node Manager looks up the domain directory fromnodemanager.domains.
This file provides additional security by restricting the Node Manager client access to the domains listed in the file. The client can execute commands only for the domains listed in nodemanager.domains.
If you create your domain with the Configuration Wizard, the nodemanager.domains file is automatically created in <WL_HOME>/common/nodemanager. If necessary, you can manually editnodemanager.domains to add a domain.
Defining the Administration Server Address
If the listen address for an administration server is not defined, when a Node Manager starts a managed server, the managed server contacts the localhost for its configuration information.
Set the listen address using the Servers > Configuration > General page in the Administration Console.
Either the listen port or the SSL listen port, or both must be enabled. This is necessary for Java-SSL Node Managers only to ensure the correct SSL handshake between the Node Manager and the administration server. If using SSL, remember that x.x.x.x is different from localhost, which is different fromwls-sysadm when it comes to the certificates.
Node Manager Configuration and Log Files
# cd /u01/app/oracle/user_projects/domains
# cd testDomain/servers/testSvr1/data/nodemanager
[root@wls-sysadm]# ll
total 24
-rw-r--r-- 1 oracle oinstall 174 Feb 5 15:56 boot.properties
-rw-r--r-- 1 oracle oinstall 6 Feb 5 15:56 testSvr1.lck
-rw-r--r-- 1 oracle oinstall 6 Feb 5 15:56 testSvr1.pid
-rw-r--r-- 1 oracle oinstall 12 Feb 5 15:56 testSvr1.state
-rw-r--r-- 1 oracle oinstall 22 Feb 5 15:56 testSvr1.url
-rw-r--r-- 1 oracle oinstall 1052 Feb 5 15:56 startup.properties
# cd
/u01/app/oracle/product/fmw/11.1.0/wlserver_10.3/common/nodemanager/
# ll
total 116
-rw-r--r-- 1 oracle oinstall 130 Feb 5 15:28 nm_data.properties
-rw-r----- 1 oracle oinstall 166 Feb 5 15:35 nodemanager.domains
-rw-r--r-- 1 oracle oinstall 69352 Feb 5 15:56 nodemanager.log
-rw-r--r-- 1 oracle oinstall 0 Feb 5 15:55 nodemanager.log.lck
-rw-r--r-- 1 oracle oinstall 900 Feb 5 15:55 nodemanager.properties
#
In managing multiple servers, a Node Manager uses multiple configuration files and outputs log files to multiple directories.
Configuration Files
Except where noted, the configuration files apply to both Java-based and script-based Node Managers.
•nodemanager.properties: This is the configuration file used by Java-based versions of the Node Manager. This file is located in <WL_HOME>/common/nodemanager, where<WL_HOME> is the location in which you installed Oracle WebLogic Server. This file needs to be updated manually for the lab.
•nodemanager.domains: This file contains mappings between the names of the domains managed by the Node Manager and their corresponding directories. This file is located in<WL_HOME>/common/nodemanager.
•nm_data.properties: This file stores the encryption data that the Node Manager uses as a symmetric encryption key. The data is stored in an encrypted form. This file is located in<WL_HOME>/common/nodemanager.
•nm_password.properties: This file stores the Node Manager username and password. This file is located in DOMAIN_HOME/config/nodemanager.
•boot.properties: A Node Manager uses this file to specify the user credentials when starting a server. This file is located inDOMAIN_HOME/servers/server_name/data/nodemanager.
•startup.properties: Each managed server instance has its own startup.propertiesfile with properties that control how the Node Manager starts up and controls the server.
A Node Manager automatically creates this file by using the properties passed to it when the administration server was last used to start the server. This allows a Node Manager client or startup scripts to restart a managed server using the same properties that were last used by the administration server.
These properties correspond to the server startup attributes that are contained inServerStartMBean and the health-monitoring attributes in ServerStartMBean. This file is located in DOMAIN_HOME/servers/server_name/data/nodemanager.
A Node Manager automatically creates this file by using the properties passed to it when the administration server was last used to start the server. This allows a Node Manager client or startup scripts to restart a managed server using the same properties that were last used by the administration server.
These properties correspond to the server startup attributes that are contained inServerStartMBean and the health-monitoring attributes in ServerStartMBean. This file is located in DOMAIN_HOME/servers/server_name/data/nodemanager.
•server_name.addr: server_name.addr stores the IP address that is added when a server starts or is migrated. This file is generated after the server IP address is successfully brought online during migration. server_name.addr is deleted when the IP address is brought offline.
The server IP address is used to validate remove requests to prevent addresses from being erroneously removed while shutting down the server.
This file is located in DOMAIN_HOME/servers/server_name/data/nodemanager.
The server IP address is used to validate remove requests to prevent addresses from being erroneously removed while shutting down the server.
This file is located in DOMAIN_HOME/servers/server_name/data/nodemanager.
•server_name.lck: server_name.lck is generated by each server and contains an internally used lock ID. This file is located inDOMAIN_HOME/servers/server_name/data/nodemanager.
•server_name.pid: server_name.pid is generated by each server and contains the process ID of the server. The Node Manager checks the process ID generated by the server during crash recovery. This file is located inDOMAIN_HOME/servers/server_name/data/nodemanager.
•server_name.state: server_name.state is generated by the server and contains the server’s current state. The Node Manager monitors the contents of this file to determine the current state of the server. Note: Do not delete or alter this file. Without this file, the Node Manager cannot determine the current state of the server.
This file is located in DOMAIN_HOME/servers/server_name/data/nodemanager.
This file is located in DOMAIN_HOME/servers/server_name/data/nodemanager.
Log Files
Use the Node Manager and Oracle WebLogic Server log files to help troubleshoot problems in starting or stopping individual managed servers.
•nodemanager.log: A Node Manager creates a log file that is located inNodeManagerHome/nodemanager.log. This log file stores data about all the domains administered by Node Manager.
This log file is generated by a Node Manager and contains data for all the domains that are controlled by a Node Manager on a given physical machine. This file is located in<WL_HOME>/common/nodemanager.
The log output is appended to the current nodemanager.log. Log rotation is disabled by default, but can be enabled by setting LogCount in nodemanager.properties.
You can view the Node Manager log file by:
This log file is generated by a Node Manager and contains data for all the domains that are controlled by a Node Manager on a given physical machine. This file is located in<WL_HOME>/common/nodemanager.
The log output is appended to the current nodemanager.log. Log rotation is disabled by default, but can be enabled by setting LogCount in nodemanager.properties.
You can view the Node Manager log file by:
-Opening the Machines Monitoring Node Manager Log page in the Administration Console
-Using the WLST nmLog command
•server_name.out: For each server instance that it controls, a Node Manager maintains a log file that contains the stdout and stderr messages generated by the server instance. If the remote start debug property is enabled as a remote start property for the server instance, or if the Node Manager debug property is enabled, the Node Manager includes additional debug information in the server output log information.Note: You cannot limit the size of the log files that a Node Manager creates. Logging to stdoutis disabled by default. This file is located indomain_name/servers/<server_name>/logs.
A Node Manager creates the server output log for a server instance in the server instance’s logsdirectory, with the name, server_name.out, where server_name is the name of the server instance.
You can view the Node Manager log file for a particular server instance by:
A Node Manager creates the server output log for a server instance in the server instance’s logsdirectory, with the name, server_name.out, where server_name is the name of the server instance.
You can view the Node Manager log file for a particular server instance by:
-Selecting Diagnostics Log Files
-Using the WLST nmServerLog command
There is no limit to the number of server output logs that a Node Manager can create.
Oracle WebLogic Server Log Files
A server instance that is under the control of a Node Manager has its own log file, in addition to the log file created by the Node Manager.
You can view the log file for a server instance by selecting Diagnostics Log Files, selecting the server log file, and clicking View.
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